kVAR to MFD Calculator
Convert reactive power in kilovolt-amperes reactive (kVAR) to capacitance in microfarads (MFD) for single-phase and three-phase AC systems.
kVAR to MFD Converter
How to Use the kVAR to MFD Converter
Converting reactive power (kVAR) into microfarads (MFD) is simple. Follow these steps:
- 1Select Phase Type: Choose between Single Phase or Three Phase configuration.
- 2Enter Reactive Power (kVAR): Input the required reactive power capacity.
- 3Enter Voltage and Frequency: Input the operational AC line voltage in volts and frequency in hertz.
- 4Click Calculate: Press the 'Calculate MFD' button to run the formulas.
How to Calculate kVAR to MFD (Step-by-Step Guide)
Converting kVAR (kilovolt-amperes reactive) to MFD (microfarads, or µF) is critical when selecting power factor correction capacitors. Shunt capacitors supply reactive current, relieving inductive load lag. The formulas and mathematical workflow are presented below.
kVAR to MFD Formulas
For Single-Phase AC:
For Balanced Three-Phase AC:
Where:
- C: Capacitance in microfarads (MFD / µF)
- kVAR: Reactive power rating
- f: System frequency in hertz (Hz)
- V: Operating voltage in volts (V)
Real-Life Scenario: Delta-Connected Capacitor Bank Sizing
A maintenance engineer sizes a 3-phase Delta correction capacitor bank rated for 10 kVAR reactive power compensation. The line-to-line operational voltage is 400V, and the grid frequency is 50Hz. Let's calculate the required capacitance per phase:
- 1Apply Three-Phase Equation:
C = (10 × 10⁹) ÷ (3 × 2 × π × 50 × 400²) - 2Calculate Denominator:
Denominator = 3 × 2 × 3.14159 × 50 × 160,000 = 150,796,447 - 3Divide Numerator by Denominator:
C = 10,000,000,000 ÷ 150,796,447 ≈ 66.31 µF
Final Output: The Delta capacitor bank requires approximately 66.31 MFD per phase.
kVAR to MFD Reference Conversion Chart
The table below displays pre-calculated capacitance ratings in microfarads (MFD) across standard kVAR values at 400V, 50Hz for a 3-phase Delta system:
| Reactive Power (kVAR) | Calculated Capacitance (MFD) |
|---|---|
| 1 kVAR | 6.63 MFD |
| 2 kVAR | 13.26 MFD |
| 5 kVAR | 33.16 MFD |
| 10 kVAR | 66.31 MFD |
| 15 kVAR | 99.47 MFD |
| 20 kVAR | 132.63 MFD |
| 25 kVAR | 165.79 MFD |
| 50 kVAR | 331.57 MFD |
25 kVAR to Microfarad
Determining a 25 kVAR to microfarad conversion for a standard 480V, 60Hz industrial feeder loop helps engineers select corrective capacitor modules. For a three-phase Delta configuration:
C = (25 × 10⁹) ÷ (3 × 2 × π × 60 × 480²) ≈ 95.80 µF.
This value dictates the required nameplate microfarad rating of the replacement capacitor bank.
3 Phase Capacitor kVAR Calculation
A standard 3 phase capacitor kVAR calculation helps calculate reactive power from known capacitance ratings. When capacitors are delta-connected across three phases, the reactive power generated is calculated as:
kVAR = (3 × CµF × 2 × π × f × VLL²) ÷ 10⁹.
This equation helps verify actual reactive power compensation in high-voltage industrial plants.
Frequently Asked Questions (FAQs)
To convert kVAR into microfarads (MFD), use the formula: C = (kVAR × 10⁹) ÷ (2 × π × f × V²) for single-phase systems, or divide by 3 in the denominator for Delta three-phase configurations.
The standard single-phase formula is: CµF = (kVAR × 10⁹) ÷ (2 × π × f × V²), and the three-phase formula is: CµF = (kVAR × 10⁹) ÷ (3 × 2 × π × f × V²).
At 400V and 50Hz frequency, 1 kVAR is equal to approximately 19.89 MFD in a single-phase system, or 6.63 MFD in a three-phase Delta configuration.
You must use the actual line-to-line AC voltage (VLL) applied across the capacitor terminals. Using nominal phase voltage instead of line voltage will introduce significant calculation errors.
For a Delta three-phase capacitor bank, use: CµF = (kVAR × 10⁹) ÷ (3 × 2 × π × f × VLL²), where VLL is the line-to-line voltage.